If you are tired of the typically boring “black box” subwoofer, Sonus faber has something for you. The “middle child” in Sonus faber’s new Gravis subwoofer lineup, the Gravis III, is a gorgeous, compact, and very musical subwoofer.

the grille

The Sonus faber Gravis III is a beautifully designed subwoofer featuring a single 10” driver in a sealed enclosure. With multiple installation options and lots of adjustability through the Gravis app, the Gravis III can be seamlessly integrated into a home theater setup or can be used to augment your main speakers in a two-channel system. When properly set up, the Gravis III doesn’t call attention to itself but delivers punchy and very nuanced bass.


Sonus faber Gravis III Subwoofer

  • Relatively compact design
  • Excellent build quality
  • Made in Italy
  • Exceptionally good looking for a subwoofer
  • Multiple setup options
  • Can be blended seamlessly with nearly any speaker

the grille


When you think of subwoofers, the name Sonus faber does not typically come to mind. While well-known for their beautiful-sounding and exquisite-looking speakers, Sonus faber has avoided the subwoofer market in recent years. The last Sonus faber-branded sub I can remember was the Cremona M sub, circa 2009. With the new Gravis lineup of subwoofers, Sonus faber is back in the subwoofer game with a vengeance. The Gravis III sits in the middle of the Gravis lineup, with the Gravis I and Gravis II (see Yongki Go’s review here) beneath it and the larger Gravis V and Gravis VI higher up the size/price scale. Designed to match the aesthetics of Sonus faber’s Lumina, Sonetto, and Olympica Nova lines, The Gravis subs raise subwoofer looks to a whole new level.


Sealed box loading, single driver, active subwoofer


1 x 10 inch (250mm) long-throw woofer


adjustable 40Hz-150Hz 24dB filtering slope


0 – 360 degrees continuously adjustable

Parametric EQ:

8 adjustable filters



Frequency Response:

down to 25Hz (@ -6dB)

Amplifier Power:

600W nominal, 900W peak, Class AB


2 x Line RCA (unbalanced) – Left and Right/LFE, 1 x Line XLR (balanced), 1 x High-level Neutrik 4-pole Speakon© plug

Dimensions (W x H x D):

15.7 x 16.3 x 19.5 inches




2 years – parts and labor, extends to 3 years if you register at sonusfaber.com within 30 days of purchase






Sonus Faber Reviews 2021, Sonus Faber Subwoofer Reviews 2021, sonus faber, subwoofer, gravis iii


the options


The Gravis III sits in the middle of Sonus faber’s five-subwoofer Gravis lineup. As such, it comes equipped with a single 10” ultra-long throw driver featuring a tri-laminated sandwich cone diaphragm woofer. This single driver sits in what is perhaps the best-looking subwoofer chassis I have ever seen. Taking design cues from the Lumina, Sonetto, and Olympica Nova speakers, the Gravis III starts with a basic cube and kicks things up a few notches aesthetically. First, the corners have been gently radiused to remove any sharp lines. Then the HDF front and sidewalls are covered in lusciously soft black leather. The icing on the cake is the top panel, which can be specified in matte walnut or wenge veneers as well as gloss piano black. These three finish choices match perfectly with Sonus faber’s Lumina, Sonetto, and Olympica Nova finishes. A small round Sonus faber button logo sits centered on the top panel. My sample Gravis III had the walnut top panel, which looked very classy and contrasted nicely with the black leather on the side and front panels. The woofer cone itself has a textured look that reminded me of carbon fiber. There is also a black cloth grille included, but I loved how the raw driver looked so I left the grille in the shipping box. The back panel houses all the connectivity options, including left and right unbalanced line-level RCA inputs, a single balanced XLR line-level input, and a high-level Neutrik Speakon© input. There is also a single volume level knob, a USB port (only for service updates), an RJ-45 jack for IP/network control, a button for wireless pairing, a single blue LED to indicate wireless pairing status, a 115/230V selector switch, and a plug for an IEC power cable. Note that there are no controls for crossover frequency or phase. These are only available in the Gravis app, which I’ll cover in the setup section. Four short rubber feet anchor the Gravis III to your floor. Overall construction quality is excellent, typical of Sonus faber. Even the volume level knob moves with very satisfying clicks. There is also an integrated wireless receiver built into the Gravis III in case you don’t want to run any wires, but to use it you will need to purchase the aptly titled, “Transmitter” (MSRP $399) from your Sonus faber dealer. Inside the chassis of the Gravis III is a 600W Class AB amplifier. Why Class AB instead of Class D amp as seen in most subwoofers today? Sonus faber cites better sound quality and improved transient response with their AB design.

the rear


With its relatively small dimensions and less than 60-pound weight, the Gravis III was pretty easy to set up. The Gravis III came in a sturdy cardboard box and was surrounded by high-density foam to ensure safe travels. All I had to do was place the box upside down, cut the bottom tape, and then flip the box over. Then I lifted the cardboard box, and the Gravis was on its feet. For this review, I had decided I would replace one of my two reference subs with the Gravis III, so I unhooked my Hsu Research VTF-3 Mark II and moved it out of the front corner of my media room. This put the Gravis III about a foot away from the left front Sonus faber Lumina V tower that I was reviewing simultaneously. I aimed the woofer directly at my primary listening position. The Gravis III looked a lot better next to the Lumina V speaker (or my reference Sonus faber Olympica III) than the gloss black Hsu unit did. My wife, who has always called my subs “dorm room refrigerators” immediately commented, “Why don’t all of your subs look like that? I like that one a lot better. And it’s smaller.” I had to agree with her in this case.

With the placement done, I connected an RCA cable to the R/LFE input jack on the Gravis III. The other end was connected to the Sub 1 output on my Marantz AV8801 pre/pro. As I planned on testing the Gravis III in a pure two-channel music setup as well as in a straight-up home theater mode, I also ran the included high-level Neutrik cable between the Gravis and my Wyred4Sound multichannel amplifier. Just take note to follow the instructions for the high-level connection carefully, as there are multiple ways to wire the four wires to your amplifier. As my main amplifier is a Class D design, I had to run three of the wires to the Left and Right-channel speaker output terminals with the fourth wire grounded to a chassis screw on the amplifier’s case. Wiring complete, it was now time to configure the Gravis III for my system.

As I mentioned earlier, you’ll need the Gravis app to do the majority of the subwoofer’s setup. I grabbed a copy of the Gravis app from the Apple App Store and installed it on my iPhone 11 Pro. The app found the Gravis III within a few seconds and prompted me to connect via Bluetooth. Even once paired, the blue connectivity light on the back of the sub continued to blink every few minutes which was very noticeable when watching movies at night. Fortunately, Sonus faber released a firmware update to address this and now the light will only blink a few times when the Gravis powers up. From the main app screen, you can see the available Gravis subs, a choice of four EQ modes, and a volume level. Choosing the sub you wish to calibrate allows you to select some additional screens. I tried the Auto EQ first. The app prompts you to place your phone near the sub and then triggers a test tone. Then you move the phone to your primary listening position and the sub plays the same tone again. While the microphone on your phone may not be as accurate as a fully calibrated mic, the app is really looking at the differences between the near-field and far-field measurements and then calculates the EQ accordingly. At least with my iPhone 11 Pro, the generated EQ seemed very accurate, particularly when using the Audiophile EQ mode which is designed to keep bass as accurate/neutral as possible. Next, I moved on to the Phase setting and adjusted it using some bass-heavy content. If you are setting up the Gravis III with just the LFE input, you will only need to adjust the overall output level via the main app page and then you should be all set.

the app

If you are using the high-level inputs, there are a few more settings you’ll want to check out. I moved on to the Low Pass screen and adjusted the Gravis manually until I liked how the bass blended with the Lumina V speakers. For tweakers who don’t wish to use the auto EQ, there is a separate screen to create up to eight parametric EQ filters. Each filter has its own central frequency, bandwidth, and gain controls. Those of you who use software like REW can have a field day with these settings if you are looking to get the most accurate bass response possible. You can also configure the Gravis III to use both the low-level/LFE input and high-level/Neutrik input simultaneously. Just set the primary volume level for the high-level/Neutrik input using the back panel volume knob or volume slider in the app and then use the trim/volume settings in your surround sound receiver or pre/pro to regulate the LFE volume level.

Curious to see how the Gravis III was doing in my room, I broke out my Audyssey Room Analyzer II Pro kit and proceeded to take some measurements. The figure below shows the raw output of the Gravis III in my system when paired with the Sonus faber Lumina Vs via the Neutrik high-level connection. All EQ and processing were disabled on the pre/pro and the sub’s Auto EQ was also disabled for these sweeps. The green trace is just the left/right pair of Lumina Vs, the yellow trace is with the Gravis III enabled. The Gravis seemed to like corner placement, as it was getting some significant boosting below 50Hz. I set the crossover at 45Hz, which seemed like the sweet spot with the Luminas. While there was a little additional energy added in the 30-40Hz range, this could easily be tamed with the Auto or Parametric EQ. Sans sub, the Lumina Vs frequency response started dropping fast around 31.5Hz which is pretty good for a small tower speaker. However, look at the additional extension the Gravis adds. With the Gravis III added (yellow trace), the output is solid until right around 22Hz. Basically, the Gravis III turned the Lumina Vs into a full-range speaker – very nice!

the frequency

In Use

the movies

With the setup complete it was time to sit down with a few Blu-ray discs and some select high-res digital audio files and get down to business. I started off using the Gravis III in a typical home theater setup utilizing the LFE input. Auto EQ was enabled on the Gravis and the Audiophile mode was selected for all my listening. I also disconnected my second reference Hsu subwoofer to ensure that I was only hearing the Gravis III. In full disclosure, I was a bit concerned over how a single Gravis III with its sole 10” driver would fare in my large (roughly 4,600 cubic feet) media room. My current reference setup consists of two subs, one is a ported 12” design, the other a sealed 15” box and both can reproduce subsonic frequencies at high output levels. You could say I’m a bit spoiled so please keep this in mind as you read my comments on movie performance.

My current reference film for bass response, Blade Runner 2049 on UHD disc, was the first real test for the Gravis III. From the opening credits, the Dolby Atmos soundtrack is an absolute beast. The sheer output level and depth of bass are just massive, adding to Hans Zimmer and Benjamin Wallfisch’s futuristic yet bleak score. The Gravis III did an admirable job of capturing the raw dynamic power of the intro scene featuring genuine analog synthesizer effects, though it couldn’t output the sheer amount of bass I’m used to in my room. The synthesizer swell around the 1:00 minute mark was forceful but didn’t take my breath away as my reference dual sub setup does. The fight between Sapper and K a few moments later packed some good punch, particularly when Sapper was slamming K against the wall of his home. The Gravis reproduced each thunk against the wall crisp and clean. I was also impressed with the overall tightness of the bass. After Sapper is “retired,” the scene where K is returning to Los Angeles has a pretty awesome score, creatively titled “Flight to LAPD” on the soundtrack. The deep bass hits sounded really good, with excellent definition between the notes. For a subwoofer with just a single 10” driver, this was a very good performance.

Next, I put the UHD Blu-ray of The Greatest Showman into my Oppo UDP-205 player. The first few minutes of the movie’s Dolby Atmos soundtrack are a great test for a subwoofer. The massive foot stomps of the circus audience had great definition and weight. I was quite impressed with how realistic they sounded. The Gravis III then transitioned very nicely to the thumping electronic bass notes that kick in a few seconds later. They had enough kick where I could feel the notes in my chest. If I had to guess, these notes are somewhere in the mid to upper 20Hz region, which the Gravis III was able to reproduce with more force. Again, the definition of the bass notes was even more impressive, dare I say, even better than my two reference Hsu’s. I played this intro scene back a few times, gradually increasing the volume until I neared the 100dB level. Only then did I start to hit the limits of the Gravis III, with a bit of compression becoming audible as I hit the limits of the woofer. The woofer cone was really moving at this point too, definitely testing the ultra-long throw design.

I finished up my movie tests with a few oldies-but-goodies from my catalog: The Dark Knight and Jurassic Park, both on regular Blu-ray disc. The shotgun blasts during the bank robbery scene (Dolby TrueHD) of The Dark Knight are a great test of pitch definition for a subwoofer and the Gravis III sailed through. The shotgun blasts sounded amazingly life-like and I have fired more than a few 12-gauges in my time. The Gravis really recreated that “blam” sound to perfection. There was also enough impact to render the sound convincingly in my space, though I can only imagine how much better two of the Gravis IIIs would have sounded in my large room. Moving on to Jurassic Park, I selected the DTS-HD Master Audio track and skipped right to the T. Rex attack scene. The initial footfalls that preclude the T. Rex’s arrival sounded very good, again with a great definition in the bass notes. However, I could tell that the Gravis III was hitting its limits as I upped the volume. There are some very deep notes here and the deepest bass just wasn’t being reproduced fully. This hurt the overall impact of the scene slightly. The Gravis III did bounce back pretty well with the T. Rex’s roar, which isn’t quite as deep in frequency. Again, these notes were more within the Gravis III’s wheelhouse and hence were reproduced at higher SPLs. For such a relatively small sub, the Gravis had a lot of kick and certainly had nothing to be ashamed of.

the music album covers

As it was time to now focus on the Gravis III from a pure music reproduction perspective, I used my Oppo player to browse to some high-resolution audio files on my NAS drive. Since I was reviewing the Sonus faber Lumina Vs at the same time, I used the same audio tracks as I did for my Lumina review, first listening to the tracks in strictly two-channel mode, then plugging the Neutrik high-level cable in to listen with the Gravis III engaged. I kept my Marantz pre/pro in Pure Direct mode the entire time and fed the two-channel signals from my Oppo player to the Marantz via analog XLR to take advantage of the Oppo’s superior DACs. After hearing how well the Gravis III had dealt with bass definition and clarity on film soundtracks, I was really excited to hear how it would fare with music.

Starting with some classical selections, I loaded up Track 19, “Finale,” from the Star Wars: Rise of Skywalker soundtrack (192kHz/24-bit FLAC, www.hdtracks.com) and focused on some of the more prominent bass sections. At the 3:26 mark, the familiar “Imperial March” kicks in with some impressive tympani notes. While I was impressed by how well these drums sounded through the Lumina Vs, adding the Gravis III into the mix really spiced things up. Easiest to hear was the increased depth of bass the Gravis brought to the table, with the drums reaching lower in frequency. The Gravis III was able to fully flesh out the deep bass notes, which I didn’t even realize I had been missing. More impressive though was the increased subtlety to the drum hits. While I could hear and feel the fluttering of the drumskins before, they now had even more definition and impact, sort of like hearing the fluttering as a highly compressed MP3 and then hearing it again in 24-bit/192kHz FLAC. Even more amazing was how the overall output of the Lumina speakers seemed to improve. It sounded like the Luminas just weren’t working as hard, which presented an ease to the sound that wasn’t there before. There was no sense of a subwoofer running, the integration between the Luminas and the Gravis III was just that good.

Next, I wanted to try some smaller scale jazz bass, so I queued up Melody Gardot’s latest album, Sunset in the Blue (96kHz/24-bit FLAC, www.hdtracks.com). The title track has a great natural bassline that once again sounded noticeably better once I added the Gravis III into the mix. The bass just sounded cleaner and more natural, with even more audible detail. There was an increased sense of depth and impact as well without things sounding over boosted. The same sense of musical ease I noticed with the Star Wars soundtrack was clearly audible here as well. The Luminas sounded like their upper bass and lower midrange had opened up a tad, which added some additional body to the sound that I thought was fantastic. The sound now reminded me more of my larger-bodied (and much higher priced) Olympica IIIs. As before, I could not tell where the Lumina’s output ended and the Gravis III’s began. It sounded like a single full-range speaker was playing.

Now knowing that the Gravis III could handle subtle bass with aplomb, I wanted to see how it could rock. Queuing up Gary Clark Jr’s. “Feelin’ Like a Million” from This Land (96kHz/24-bit FLAC, www.hdtracks.com) was a fun experience. With the Gravis III engaged, the thumping reggae bass line came through deeper and with even more punch. I went from being able to feel the notes in my chest to the hairs on my arm starting to dance a bit with the increased output. The differences between the individual bass notes became even easier to hear, even as I cranked up the volume to a very high level. I have always thought that 10” woofers offer some of the most accurate bass response out there, and the Gravis III certainly delivered on that mark. Integration between the Gravis III and the Lumina Vs continued to be exceptional with the sound seemingly emanating from a single speaker.


the wenge angle

At first glance, $2,750 for a subwoofer with a single 10” driver seems a bit steep, especially when that subwoofer doesn’t deliver ultra-deep subsonic frequencies or massive output levels in large rooms. However, considering the SONUS FABER GRAVIS III SUBWOOFER’s beautiful design and amazing ability to make your primary speakers sound so much better with music sources, it is worth every penny to the right buyer.

  • Exceptional pitch definition
  • Very fast, tight bass for music
  • Good output and bass depth for a 10” sealed sub
  • Very easy to configure with the Gravis app
  • Parametric EQ for tweakers
  • Auto-EQ works well
Would Like To See
  • True 20Hz capability and additional output would be great

While the Gravis III performed admirably with movie soundtracks, I don’t feel that it was designed to be a butt-shaking home theater subwoofer. Given its single 10” driver and relatively small, sealed cabinet, it doesn’t offer the exceptionally high output or 20Hz (or lower) extension that many movie aficionados crave, particularly in a larger room. The larger Gravis V or VI would be a better choice for that scenario with their 12” (or dual 12” inch in the case of the Gravis VI) woofers. However, in a system where accurate music reproduction takes priority, the Gravis III is truly exceptional, blending seamlessly with your main speakers to augment their bass response. The additional bass the Gravis III adds to your main speakers is fast, tight, and incredibly musical, particularly when using the Neutrik high-level input and taking advantage of the myriad of setup options offered by the Gravis app. With the Gravis III configured properly, your main speakers effortlessly punch out deep notes with authority. The Gravis III has the amazing ability to make your primary speakers sound bigger and better like their cabinet volume or woofer size doubled. If you own Sonus faber’s Lumina, Sonetto, or Olympica Nova speakers and desire a relatively compact high-performance subwoofer that looks just as good as your speakers, then the Gravis III (or two of them) may be just what the doctor ordered. Even if you don’t have Sonus faber speakers, the Gravis III’s great looks, exceptional bass accuracy, and first-class disappearing act could make it a fantastic addition to your system.